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Kombucha Tea

Other common name(s): Manchurian tea, Kargasok tea, tea fungus

Scientific/medical name(s): none

Description

Kombucha tea is made by fermenting sweetened black tea with a flat, pancake-like culture of yeasts and bacteria called the "Kombucha mushroom". It is not actually a mushroom, but is called one because of the shape and color of the sac that forms on top of the tea after it ferments. The culture used in Kombucha tea varies, but consists of several species of yeast and bacteria. It may include Saccharomycodes ludwigii, Schizosaccharomyces pombe, Brettanomyces bruxellensis, Bacterium xylinum, Bacterium gluconicum, Bacterium xylinoides, Bacterium katogenum, Pichia fermentans, Candida stellata, and Torula species, among others.

Because there are several types of yeast and bacteria that can grow under these conditions, different Kombucha brews may contain different types. Since cultures and preparation methods vary, Kombucha tea may contain contaminants such as molds and fungi, some of which can cause illness. After the tea is made, it is usually highly acidic and contains alcohol, ethyl acetate, acetic acid, and lactate.

Overview

Available scientific evidence does not support claims that Kombucha tea promotes good health, prevents any ailments, or works to treat cancer or any other disease. Serious side effects and occasional deaths have been linked with drinking Kombucha tea.

How is it promoted for use?

Kombucha tea has been promoted as a cure-all for a wide range of conditions including baldness, insomnia, intestinal disorders, arthritis, chronic fatigue syndrome, multiple sclerosis, AIDS, and cancer. Supporters say that Kombucha tea can boost the immune system and reverse the aging process. Kombucha tea is said to contain antioxidants, compounds that block the action of free radicals (activated oxygen molecules that can damage cells). For people who have cancer, proponents claim the tea can improve the body's defenses (especially in the early stages of cancer) by detoxifying the body and enhancing the immune system. After the body has been detoxified, the tea is said to help repair and balance the body and fight off disease.

What does it involve?

The culture used in Kombucha tea varies, but consists of several species of yeast and bacteria. It may include Saccharomycodes ludwigii, Schizosaccharomyces pombe, Brettanomyces bruxellensis, Bacterium xylinum, Bacterium gluconicum, Bacterium xylinoides, Bacterium katogenum, Pichia fermentans, Candida stellata, and Torula species, and others.

Kombucha tea is made by steeping the "mushroom" culture in tea and sugar for about a week. During this process, the original mushroom floats in the tea and produces a "baby mushroom" on its surface. These new mushrooms can be passed along to other people for starting their own cultures or can be kept to make new batches of the tea when the original mushroom "goes bad" (indicated when it turns dark brown). Proponents often recommend drinking very small daily doses of the tea (1 to 2 ounces) to start, and slowly increasing it over a few days or weeks.

Some proponents also encourage people to remove all chemicals from their diets and eat only fresh fruits and vegetables in order to help the "detoxification" process. They may also be advised to quit smoking and avoid caffeine, soft drinks, alcohol, hormone-fed meat, fertilized or sprayed foods, preservatives, and artificial coloring and flavoring.

Kombucha mushroom cultures can be obtained from commercial manufacturers in the United States, but most people get Kombucha mushrooms from friends. Because of increased demand, some companies now sell bottles of brewed Kombucha tea and beverages that are a mixture of Kombucha tea with fruit juices or other flavorings. Other products include capsules made from the dried tea and Kombucha liquid extract, drops of which are put under the tongue.

What is the history behind it?

Kombucha tea originated in East Asia and was introduced into Germany at the turn of the century. Since the early 19th century, Kombucha tea has been promoted as an immunity-boosting tea that can strengthen the body against many ailments. It became more widely used in the United States partly because it can be made at home. It is especially popular among people with HIV and the elderly because of claims it can boost immunity and slow aging.

What is the evidence?

No human studies have been published in the available scientific literature that support any of the health claims made for Kombucha tea. There have, however, been reports of serious complications and death linked to the tea.

Are there any possible problems or complications?

This product may be sold as a dietary supplement in the United States. Unlike companies that produce drugs (which must be tested before being sold), the companies that make supplements are not required to prove to the Food and Drug Administration that their supplements are safe or effective, as long as they don't claim the supplements can prevent, treat, or cure any specific disease.

Some such products may not contain the amount of the herb or substance that is on the label, and some may include other substances (contaminants). Actual amounts per dose may vary between brands or even between different batches of the same brand. In 2007, the FDA wrote new rules to improve the quality of manufacturing for dietary supplements and the proper listing of supplement ingredients. But these rules do not address the safety of the ingredients or their effects on health.

Most such supplements have not been tested to find out if they interact with medicines, foods, or other herbs and supplements. Even though some reports of interactions and harmful effects may be published, full studies of interactions and effects are not often available. Because of these limitations, any information on ill effects and interactions below should be considered incomplete.

Because several types of yeast and bacteria can grow under Kombucha tea's brewing conditions, different Kombucha teas may contain different varieties. Since cultures and preparation methods vary, Kombucha tea may contain contaminants such as molds and fungi, some of which can cause illness. After the tea is fermented, it is usually highly acidic and contains alcohol, ethyl acetate, acetic acid, and lactate.

In April 1995, two women who had been drinking the tea daily for 2 months were hospitalized with severe acidosis -- an abnormal increase of acid levels in body fluids. Both had high levels of lactic acid upon hospitalization. One woman died of cardiac arrest 2 days after admission. The second woman's heart also stopped, but she was stabilized and recovered. The mushrooms used by both women came from the same "parent" mushroom. While no direct link to Kombucha tea was proven in this case, the U.S. Food and Drug Administration (FDA) has warned consumers to use caution when making and drinking the tea.

In 2009, a 22-year-old man was hospitalized with trouble breathing, fever, confusion, and high lactic acid levels within 12 hours after drinking Kombucha tea. He recovered, but his doctor believed that the tea was the cause of his lactic acidosis. This is a rare but serious and often fatal condition.

Because deaths have been linked with the tea, drinking excessive amounts is not recommended. Several experts warn that since home-brewing facilities vary a great deal, the tea could become contaminated with harmful germs. These germs could be especially dangerous to people with HIV, cancer, or other immune problems. Anthrax of the skin has been reported, as has jaundice, a yellowing of the skin and eyes that is usually caused by liver damage. Allergic reactions, possibly to molds in the tea, have been reported.

Kombucha tea should not be brewed in ceramic, lead crystal, or painted containers, as the acidity of the tea can cause it to absorb harmful elements from its container. Lead poisoning has been reported in at least two people who brewed Kombucha tea in a ceramic pot.

Since the potential health risks of Kombucha tea are unknown, anyone with an immune deficiency or any other medical condition should consult a physician before drinking the tea. Women who are pregnant or breast-feeding should not use this tea. Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences.

Additional Resources

More information from your American Cancer Society

The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-227-2345).

Woolan M. A Strange Brew May Be a Good Thing. March 24, 2010. Accessed at http://www.nytimes.com/2010/03/25/fashion/25Tea.html?_r=1 on October 15, 2010.

Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.